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Bandgap engineering of two-dimensional C3N bilayers


Carbon materials such as graphene are of potential use in the development of electronic devices because of properties such as high mechanical strength and electrical and thermal conductivity. However, technical challenges, including difficulties in generating and modulating bandgaps, have limited the application of such materials. Here we show that the bandgaps of bilayers of two-dimensional C3N can be engineered by controlling the stacking order or applying an electric field. AA′ stacked C3N bilayers are found to have a smaller bandgap (0.30 eV) than AB′ stacked bilayers (0.89 eV), and both bandgaps are lower than that of monolayer C3N (1.23 eV). The larger bandgap reduction observed in AA′ stacked bilayers, compared with AB′ stacked bilayers, is attributed to the greater pz-orbital overlap. By applying an electric field of ~1.4 V nm−1, a bandgap modulation of around 0.6 eV can be achieved in the AB′ structure. We also show that the C3N bilayers can offer controllable on/off ratios, high carrier mobilities and photoelectric detection capabilities.

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Fig. 1: Stacking and bandgap of the C3N bilayer.
Fig. 2: Band structure and partial charge distribution of the C3N bilayers with AA, AA′, AB, AB′ stackings.
Fig. 3: Structure characterization and bandgap measurement of the C3N bilayers with AA′ and AB′ stackings.
Fig. 4: Bandgap engineering of the C3N bilayer induced by external electric fields.

Data availability

The data that support the plots within this manuscript and other findings of this study are available from the corresponding authors upon reasonable request. Source data are provided with this paper.


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This work was financially supported by the National Natural Science Foundation of China (grants 21673075, 51725204, 21771132, 51972216, 52041202, 11774368, 11804353, 11704204, 61971035, 61901038 and 61725107), National Key Research and Development Program of China (2019YFA0308000, 2020YFA0308800 and 2020YFA0406104), Innovative Research Group Project of the National Natural Science Foundation of China (51821002), the Australian Research Council through the Discovery Early Career Research Program (DE170101403), Natural Science Foundation of Jiangsu Province (BK20190041), Key-Area Research and Development Program of GuangDong Province (2019B010933001), Collaborative Innovation Center of Suzhou Nano Science & Technology, the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) and the 111 Project. B.I.Y. thanks the Office of Naval Research (N00014−18-1-2182) and the Army Research Office (W911NF-16-1-0255) for support. W.W. was supported by a scholarship from the China Scholarship Council. The computations were performed at ECNU Multifunctional Platform for Innovation (001), Shanghai Supercomputer Center and using computational resources of the NCI through the National Computational Merit Allocation Scheme supported by the Australian Government, the Queensland Cyber Infrastructure Foundation and the University of Queensland Research Computing Centre. We thank D. Sun in East China Normal University for useful discussions.

Author information




Q.Y. and D.J.S. conceived and supervised the theoretical calculations for the work. Z.K., Y.W. and G.D. supervised the experimental part of the project. W.W., W.P., Z.C. and L.W. carried out the theoretical calculations. S.Y., Y.Y. and P.H. synthesized monolayer and bilayer C3N. S.Y., Y.Y. and G.W. characterized the monolayer and bilayer C3N. S.Y., G.W. and L.Z. fabricated C3N devices and analysed experimental data. T.Z., L.L., Q.Z. and Y.W. conducted the scanning tunnelling spectroscopy/scanning tunnelling microscopy measurements. A.B. and B.I.Y. analysed the data and discussed the manuscript. Q.Y., W.W., S.Y. and D.J.S. wrote and revised the manuscript.

Corresponding authors

Correspondence to Guqiao Ding, Zhenhui Kang, Debra J. Searles or Qinghong Yuan.

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The authors declare no competing interests.

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Peer review information Nature Electronics thanks the anonymous reviewers for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–26, Discussion and Tables 1–4.

Source data

Source Data Fig. 1

Source data for Fig. 1a,c.

Source Data Fig. 2

Source data for Fig. 2a.

Source Data Fig. 3

Source data for Fig. 3g,j,n.

Source Data Fig. 4

Source data for Fig. 4b–d.

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Wei, W., Yang, S., Wang, G. et al. Bandgap engineering of two-dimensional C3N bilayers. Nat Electron 4, 486–494 (2021).

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